It is common practice in the air transport industry to provide preconditioned air to an aircraft parked at a jetway from a ground source, rather than to use the craft's onboard heating or air-conditioning systems. For this reason, aircraft are typically provided with a standard hatch door and connector. When the hatch door is opened, a ground-based source of preconditioned air is connected to the connector through a length of hose, the distal end of which is attached to an adapter chute designed to mate with a standard ring connector on the aircraft. As explained in one of the prior art references, the standard for the ring connector is set by Military Standard MS 33562(ASG) entitled "Connection, Aircraft Ground Air Conditioning, 8 inch, minimum requirements."
In designing an adapter chute for attaching the preconditioned air hose to the aircraft, considerations which are considered include the weight and durability of the chute body, the reliability and ease of use of the clamps and the quality of air-tight seal obtained between the chute and the connector.
In attempting to improve the adapter chute, the designer is obviously constrained by the limitation that the chute must mate with the standard ring connector. However, the patent art demonstrates that some variation in design is clearly possible. For example, one patent notes that the type of chute previously used (in 1993) was made of metal, was cone-shaped, had no handles and had a bar-type clamp for clamping the chute to the connector. Advantages provided by that inventor include the use of high-density polyethylene instead of metal, use of a conical bottom and a cylindrical top, as well as the introduction of handles, and the use of heavy duty clamps featuring TEFLON hooks.
One type of chute assembly known in the prior art engages the ring connector by inserting L-shaped hooks through slots in the ring connector and then rotating the entire chute, while compressing it against the ring connector to allow the hooks to engage the end edges of the slots. Another type of chute assembly known in the prior art has spring-loaded latches which are inserted through the slots of the ring connector while the chute is compressed against the ring connector. These spring-loaded latches then engage the side edges of the slots. One of the patents notes the relative expense of the ring connector on the aircraft and how damage to the ring connector.
It is therefore a desired advantage not found in the prior art to provide an improved adapter chute which is compatible with the standard ring connector, but which uses a smooth and simple rotation of a handle to simultaneously compressively seal the chute to the ring connector and cause a pair of clamps to engage slots in the ring connector.